Project Summary Preventative interventions involving video-feedback programs to promote parenting (VIPP; Juffer et al., 2008) have been shown to be successful in improving maternal sensitivity and infant-mother attachment security (Bakermans-Kranenberg et al., 2008). However, interventions might be substantially more effective if broader elements of family systems were also addressed, including father-child and inter-parental relationships, particularly given the growing body of evidence that highlights the importance of father involvement and positive engagement in children's socio-emotional development. Infancy is a particularly sensitive and vulnerable period not only for the child but also for the parents who often experience heightened daily stress, parenting demands, work-family role strain, and inter-parental discord associated with changes in the family (Feeney et al., 2001).The proposed longitudinal study addresses major gaps by testing the effectiveness of family-wide preventative interventions designed to promote healthy development and functioning in infants, mothers, and fathers, including low-income families. This three-phase study involves a rigorous randomized clinical trial (RCT) approach and will involve a demographically diverse sample of 400 families. Phase I involves a lab and home pre-test (infants 6 months of age) and 8-week intervention period; Phase II (12 months) includes an initial post-test, and Phase III (16-18 months) involves a second post-test. Families will be randomly assigned to one of four conditions: sensitivity intervention (SI), couples intervention (CI), both (SI + CI) or control. Specific aims of the study include: (1) An evaluation of the effectiveness of the SI, CI, and SI+CI interventions at improving parental sensitivity, parental efficacy, parenting stress, inter-parental conflict, infant affective development, attachment security, behavior problems, and socio-emotional competence; (2) A test of the mechanisms through which change in behavior occurs. For example, relations between SI participation in Phase I and child attachment in Phase III may be mediated by enhanced parent sensitivity in Phase II. Relations between CI participation and child outcomes may be mediated by inter-parental functioning and more effective communication skills; (3) An examination of factors that moderate the effectiveness of the interventions, determining which families benefit the most. Potential moderators include demographic characteristics, family (dis)organization, parents' own caregiving history, parents' depressive and anxious systems, and infant negative temperament; (4) Mother-father comparisons on direct effects, mediating mechanisms and moderating processes. This study builds upon past research towards increasing children's emotional security in multiple family relationships by testing new directions in preventative interventions in infancy, addressing the mother-child, father-child, and mother-father relationships. The goal is to foster children's socio-emotional development and security through cost-effective family-wide interventions in infancy that promote sensitive parent-infant interactions and improved inter-parental communication.